1. Field of the invention
The present invention relates to a bicycle type training machine. More specifically, the present invention relates to a bicycle type training machine in which load amount or quantity of motion is controlled by variable braking force applied to a rotation shaft of a pedal crank.
2. Description of the prior art
In a bicycle, due to sufficient inertia, it is possible to smoothly move or rotate the pedals even if the pedals are located at the top dead point and/or the bottom dead point of their rotational path of travel. However, in a bicycle type training machine, since sufficient inertia can not be obtained, the foot or legs of the user must bear a change in the load amount during operation. Thus it is impossible to smoothly move or rotate the pedals when they are located at the top dead point and/or the bottom dead point of their path of travel.
One piece of prior art employs a flywheel system in order to reduce fluctuation of the load. In this system, a flywheel having a relatively large inertia value is utilized to enable the pedals to rotate smoothly. However, the flywheel system only serves to reduce the fluctuation of the load and can not control the load amount to fit to the leg strength of the user.
A training machine utilizing a braking device based on an eddy current system is disclosed in, for example, Japanese Patent Laying-open No. 60-14876 laid-open on Jan. 25, 1985. This machine overcomes some of the disadvantage of the flywheel system. However, since braking force is obtained by the eddy current, a specific electric eddy current generator is needed. Therefore, one may only use this device near a source of electrical current.
A machine circumventing the inconvenience of the above eddy current system employs a direct current motor to control the load amount, as proposed in, for example, Japanese Patent Laying-open No. 56-85365 laid-open on Jul. 11, 1981. In this prior art, the output of a direct current motor is varied as a function of the changing pedal rotation rate, thus reducing the load fluctuation.
The above described training machine simulates a constant training state but does not control the quantity of motion or the load amount. The reason is that the output of the direct current motor is varied by only the changing pedal rotation rate.